1. Field of the Invention
The present invention relates to a processing method for a discharge nozzle which sublimes and processes, by means of laser light, a discharge nozzle in a liquid jet recording head for adhering droplets on a recording medium by flying droplets of recording liquid or the like, and a manufacturing method for a liquid jet recording head.
2. Related Background Art
In a liquid jet recording apparatus (ink jet printer) for adhering droplets on a recording medium by flying droplets of recording liquid such as ink, printing quality much depends upon characteristic properties of a nozzle portion, which is a portion for discharging recording liquid, and the characteristic properties of this nozzle portion are substantially determined by a variation in nozzle diameter and shape of the nozzle. As the generally used two methods to form this nozzle, there are a method of forming using a metallic plate in accordance with an electroforming method or an electrical discharge method, and a method of subliming and processing high polymeric organic resin material using a high energy laser such as an ultraviolet laser represented by an excimer laser. The latter, a fine processing method using ultraviolet lasers, has generally been employed.
In this ultra violet laser processing method, when processed at a suitable laser energy density to sublime and process. high polymeric organic resin material, there is provided so-called taper-shaped processing characteristic properties in which the processing area gradually decreases from the laser incoming radiation side to the laser outgoing radiation side. The shape of the nozzle required in order to raise the printing quality of the liquid jet recording head is a tapered configuration, which tapers toward the discharge side of the recording liquid. Therefore, the laser processing method has been performed by laser irradiation from the supply side of the recording liquid, that is, concerning a plate for forming the discharge nozzle, there has been adopted a process of combining the plate with a member for supplying the recording liquid after the discharge nozzle is processed and formed.
The discharge nozzle, however, typically requires a length of several tens xcexcm to about 100 xcexcm in terms of the printing quality, and the thickness of the plate for forming this nozzle has naturally also the same dimension. This discharge port formation plate is a very thin, easily transformable member, must be laser processed from the liquid supply side, and must be combined with a member of supplying the recording liquid after the discharge nozzle is formed by processing. This has led to a problem that after the combination, stresses cause deformation in the discharge port formation plate, a plurality of discharge nozzles lined up in the same direction cannot be formed, but the discharge direction of the recording liquid becomes random, thus deteriorating the printing quality.
In order to solve such a problem, there has been proposed a method of processing and forming the discharge nozzle after the liquid jet recording head is assembled, that is, a discharge nozzle processing method for subliming and forming discharge nozzles of a tapered configuration, which tapers in the liquid discharge direction, on the discharge port formation plate by bringing a mask plate, on which a shape of the discharge port to be formed has been patterned, into tight contact with the discharge port formation plate, on which a plurality of discharge ports in the liquid jet recording head are formed, on the liquid discharge side, and irradiating high energy ultra violet laser from the mask plate side.
However, in the method of processing and forming the discharge nozzle after the above described liquid jet recording head is assembled, since the discharge nozzle is processed and formed by irradiating laser light from the outside, which is the liquid discharge side of the discharge port formation plate, there arises a problem that the irradiation of the laser light deteriorates a repellent coated layer on the liquid discharge-side surface of the discharge port formation plate, thus lowering the water repellency. Further, there arises a problem that a fusing phenomenon due to heat accumulation of the laser light irradiation and some optical blurring at the outer periphery of the laser irradiation pattern cause an edge of the discharge nozzles on the liquid discharge side to become inactive as shown in FIG. 4.
A sharp edge of the discharge nozzle on the liquid discharge side is very important to determine the discontinuation effect of the recording liquid during liquid discharge and the direction of flying of droplets, and therefore, there arises a problem that the inactive edge on the liquid discharge side causes errors in placement positions of droplets or mist due to dispersion of droplets.
In addition, a secondary product (debris) caused by the laser processing disperses within liquid passages in the liquid jet recording head, and the surface energy and hydrophilic force of the debris thus dispersed affects the flow of recording liquid and adheres to a heating conductor for generating discharge energy of the recording liquid. Thus, this contaminated heating conductor deteriorates the heat generating efficiency.
One of objects according to the present invention is to provide a processing method of a discharge nozzle for a liquid jet recording head and a manufacturing method of the liquid jet recording head capable of forming the edge of the discharge nozzle on the liquid discharge side sharp without causing any damage to the repellent layer on the surface, on the liquid discharge side, of the discharge port formation plate when laser processing the discharge nozzle by means of irradiation of laser light from the liquid discharge side of the discharge port formation plate in the liquid jet recording head, and further of stabilizing the discharge of droplets and improving the printing quality by excluding secondary products which disperse and adhere within liquid passages in the liquid jet recording head.
It is another object according to the present invention to provide a processing method for a discharge nozzle in a liquid jet recording head for processing and forming the discharge nozzle on a discharge port formation plate by irradiation of laser light from the liquid discharge side of the discharge port formation plate of the liquid jet recording head, comprising the steps of providing a surface of the discharge port formation plate on the liquid discharge side with a sacrifice layer made of material capable of being processed by the laser light; processing and forming a discharge nozzle on the discharge port formation plate by irradiation of laser light; and removing the sacrifice layer.
Also, it is a further object according to the present invention to provide a processing method for a discharge nozzle in a liquid jet recording head for processing and forming the discharge nozzle on a discharge port formation plate by irradiation of laser light from the liquid discharge side of the discharge port formation plate of the liquid jet recording head, comprising the steps of: providing sacrifice layers made of material capable of being processed by the laser light for both surfaces of the discharge port formation plate on the liquid discharge side and on the liquid supply side, or the surface of the discharge port formation plate on the liquid discharge side and wall surface of the liquid passage; processing and forming a discharge nozzle on said discharge port formation plate by irradiation of laser light; and removing the sacrifice layer.
In a processing method for the discharge nozzle for the liquid jet recording head according to the present invention, it is preferable to use water-soluble resin as the sacrifice layer, to form the sacrifice layer by applying the water-soluble resin, and to remove the water-soluble resin as the sacrifice layer by rinsing after the discharge nozzle is processed. Also, it is preferable to use resinous film as the sacrifice layer, to vacuum bond the resinous film onto the surface of the discharge port formation plate on the liquid discharge side, and to remove the resinous film as the sacrifice layer by mechanically peeling after the discharge nozzle is processed.
In a processing method for a discharge nozzle for a liquid jet recording head according to the present invention, it is possible to arrange the structure such that a high energy ultra violet laser is used as a laser used to process the discharge nozzle, and resin as the sacrifice layer and the discharge port formation plate are sublimed and processed by a photo-chemical reaction process, or it is also possible to arrange the structure such that a high energy short pulse oscillation laser is used as a laser used to process the discharge nozzle, and resin as the sacrifice layer and the discharge port formation plate are sublimed and processed by a thermo-chemical reaction process.
It is an another object according to the present invention to provide a method for manufacturing a liquid jet recording head for processing and forming a discharge nozzle on a discharge port formation plate by irradiation of laser light from the liquid discharge side of the discharge port formation plate of the liquid jet recording head, the method comprising the steps of: providing the surface of the discharge port formation plate on the liquid discharge side with a sacrifice layer made of material capable of being processed through the laser light; processing and forming the discharge nozzle on the discharge port formation plate by irradiation of laser light; and removing the sacrifice layer.
Also, it is an additional object according to the present invention to provide a method for manufacturing a liquid jet recording head for processing and forming a discharge nozzle on a discharge port formation plate by irradiation of laser light from the liquid discharge side of the discharge port formation plate of the liquid jet recording head, the method comprising the steps of: providing sacrifice layers made of material capable of being processed through the laser light for both surfaces of the discharge port formation plate on the liquid discharge side and on the liquid supply side, or the surface of the discharge port formation plate on the liquid discharge side and a wall surface of the liquid passage; processing and forming the discharge nozzle on the discharge port formation plate by irradiation of laser light; and removing the sacrifice layer.
In a manufacturing method for a liquid jet recording head according to the present invention, it is preferable to process and form the discharge nozzle by irradiation of laser light from the discharge port formation plate on the liquid discharge side after, of each member constituting the entire liquid jet recording head, the discharge port formation plate, on which at least a plurality of discharge ports are formed, and a member for holding the discharge port formation plate are combined.
In a manufacturing method for a liquid jet recording head according to the present invention, it is preferable to use water-soluble resin as the sacrifice layer, to form a sacrifice layer by applying the water-soluble resin, and to remove the water-soluble resin as the sacrifice layer by rinsing after the discharge nozzle is processed. Also, it is preferable to use resinous film as the sacrifice layer, to vacuum bond the resinous film onto the surface of the discharge port formation plate on the liquid discharge side, and to remove the resinous film as the sacrifice layer by mechanically peeling after the discharge nozzle is processed.
In a manufacturing method for a liquid jet recording head according to the present invention, it is possible to arrange the structure such that a high energy ultra violet laser is used as a laser used to process the discharge nozzle, and resin as the sacrifice layer and the discharge port formation plate are sublimed and processed by a photo-chemical reaction process, or it is also possible to arrange the structure such that a high energy short pulse oscillation laser is used as a laser used to process the discharge nozzle, and resin as the sacrifice layer and the discharge port formation plate are sublimed and processed by a thermo-chemical reaction process.
In a manufacturing method for a liquid jet recording head according to the present invention, it is preferable that the surface of the discharge port formation plate on the liquid discharge side be formed with a repellent layer, which has been coated with water repellent in advance.
According to the present invention, it becomes possible to form the edge of the discharge nozzle on the liquid discharge side in a sharp shape, and the repellent layer on the surface of the orifice plate on the liquid discharge side is not subjected to any degradation and damages caused by the irradiation of laser light because of the existence of the sacrifice layer, but can be protected. Further, the inside surface of the orifice plate on the liquid supply side and the liquid passage wall surface within the liquid jet recording head are attached with sacrifice layers, and the sacrifice layers are removed after laser processing, whereby it is possible to exclude debris, which is a secondary product caused in the laser processing, and to prevent the interior of the liquid jet recording head from being contaminated by debris. Therefore, it is possible to stabilize the discharge of droplets and to improve the flying speed of the droplets, thus remarkably improving the printing quality of the liquid jet recording head and enabling high-speed printing.